EP3552724B1 - Wire puller having a sensor device for determining the wire position and method for operating a wire puller - Google Patents

Description

State of the art

To produce nails or screws, for example, from a wire, a raw wire wound into a coil is usually used. In most cases, the cross-section of the raw wire has to be reduced to a target cross-section. The cross section of the wire can have different geometric shapes and, for example, square, but is mostly round.

Wire drawing devices with which the cross section of a wire can be reduced in a deformable manner are known from the prior art. So the document discloses DE 10 2005 049 018 A1 a drawing disk of a wire drawing device and a method for reducing the cross section of a wire with a wire drawing device

U.S. 3,709,021 A , which forms the basis for the preamble of claims 1 and 9, also shows a wire drawing device and a method of operating a wire drawing device.

In order to avoid unnecessary journeys, the wire is usually fed directly from the wire drawing device to a downstream processing machine. It is important to adapt the processing speeds of the two machines to one another, i.e. to feed the wire out of the wire drawing device at the speed at which the wire is processed by the downstream processing machine.

To this end, it has hitherto been customary to use a mechanical dancer arm. In the case of the dancer arm, the wire arch is guided from the wire drawing device via a pulley to the downstream processing machine. The deflection roller is acted upon with a counterpressure and equipped with a position measuring system. If more wire is drawn in by the following processing machine than is provided by the wire drawing device, the mechanical tension of the wire between the wire drawing device and the following processing machine increases the pulley is shifted against the counter pressure, which is registered by the position measuring system. The path measuring system then regulates the speed with which the wire drawing device provides wire via a frequency controller and increases the speed of the drawing disk of the wire drawing device. If, on the other hand, more wire is fed from the wire drawing device to the downstream processing machine than it is processed, the tension of the wire on the deflection roller is reduced and this moves following the counterpressure, which is also registered by the displacement measuring system. The position measuring system then regulates the speed at which the wire drawing device makes wire available via the frequency controller and reduces the speed of the drawing disk of the wire drawing device.

However, this method has significant disadvantages. Especially with longer lengths of wire to be processed and higher speeds, the mechanical contact of the wire with the deflection roller leads to impairment of the material quality of the wire; in particular, pressing the wire against the deflection roller of the dancer arm leads to knocks and kinks.

Disclosure of the invention

It is therefore an object of the present invention to provide a wire drawing device which does not have the disadvantages of the prior art, but allows the speed of the wire drawing device and the subsequent processing machine to be coordinated without having to subject the wire to mechanical stress. Furthermore, it is an object of the present invention to provide a method for operating a wire drawing device which likewise does not have the disadvantages of the prior art, but rather enables the speed of the wire drawing device and the subsequent processing machine to be better coordinated with one another without that the wire is exposed to mechanical stress.

This object is achieved by the wire drawing device of claim 1 for reducing the cross section of a wire.

The wire drawing device according to the invention makes it possible that the wire, which is particularly sensitive in the loading direction transverse to its main direction of extension, is not kinked by the kickback force of a dancer arm. This is achieved by guiding the wire from the drawing disk in an arc essentially orthogonal to the direction of the wire guide element, typically along a plane parallel to the main extension plane of the drawing disk, through the wire guide element to the downstream processing machine and determining the position of the wire in the wire guide element without contact. If the following processing machine processes the same amount of wire as is provided by the wire drawing device, the position of the wire in the wire guide element remains stable. If the position of the wire in the wire guide element changes, this is detected and the speed of the drawing disk is automatically adjusted accordingly.

Typically, wire material is drawn in discontinuously, that is, in cycles, from the downstream processing machine, while the wire is continuously supplied from the drawing disk. The wire material guided through the wire guide element therefore represents a material buffer in the area of the wire guide element. As a result of the discontinuous drawing of the wire into the downstream processing machine, the wire position in the wire guide element swings around a zero position. If the oscillation of the wire position is within a target range, the drawing disk supplies as much wire as is drawn in by the following processing machine on average over time. The time average is understood here to mean that the time averaging takes place over a period of time which corresponds to an integral multiple of a cycle of the downstream processing machine. If the oscillation leaves the target range, the drawing pulley feeds more or less wire than the next The processing machine moves in as averaged over time, the speed of the drawing disk is regulated based on the distance of the oscillation from the target range, so that the vibration returns to the target range and as much wire is supplied from the drawing disk as the subsequent processing machine draws in as averaged over time.

It is conceivable that the wire control device is attached to a holding frame.

The direction of the wire guide element is preferably horizontal, particularly preferably the direction of the wire guide element is horizontal and, in the horizontal plane, aligned in a line with the drawing disk and the downstream processing machine. It is conceivable that the wire control device has a control unit with which the speed of the drawing disk can be regulated via a frequency controller of the drive of the drawing disk. It is also conceivable that the control unit has a PID controller with which a control characteristic can be set. In particular, overshoots in the speed control can be avoided in this way.

Advantageous refinements and developments of the invention can be found in the subclaims and the description with reference to the drawings.

According to a preferred embodiment of the present invention it is provided that the wire control device has a housing, the housing having an upper side part and a lower side part. It is conceivable that the housing also has a right side part and a left side part. This makes it possible to protect the measuring area and in particular the sensor device from mechanical damage or from contamination. Furthermore, the housing allows a stable and stable mounting on a holding frame and thus an improvement of the measurement results and thus the regulation of the speed of the drawing pulley.

According to a further preferred embodiment of the present invention it is provided that the means for leading the wire through are each a gap along the direction of the wire guide element in the upper side part and in the lower side part. In this way, a shaft consisting of two columns, preferably a vertical shaft, for the passage of the wire is implemented in an advantageously stable manner. It is also possible to prevent uncontrolled movements of the wire, for example transversely to the direction of the wire guide element, to stabilize the guidance of the wire and thus to protect the surroundings of the wire drawing device from uncontrolled movements and deflections of the wire.

The measuring light barrier should be described as the first option (sensor device at least one light grid along the direction of the wire guide element) Light grid consists of a pair of measuring light barriers, which are arranged parallel, opposite. According to a further preferred embodiment of the present invention, it is provided that the sensor device has an optical Distance sensor, preferably a light barrier, particularly preferably a distance-measuring light barrier.

Optical distance sensors of excellent quality can be obtained inexpensively as a standard component and are outstandingly suitable as sensors of the sensor device of the present invention. Optical distance sensors, in particular light barriers, are sufficiently robust and have a long service life.

It is conceivable that the sensor device has at least one optical distance sensor at one end of the wire guide element, a measuring section of the optical distance sensor being aligned along the direction of the wire guide element. However, it is also conceivable that the sensor device has at least one light grid along the direction of the wire guide element. Furthermore, it is conceivable that the sensor device has a plurality of light barriers, the light barriers of the plurality of light barriers being arranged next to one another along the direction of the wire guide element, measuring sections of the light barriers of the plurality of light barriers being essentially orthogonal to Direction of the wire guide element and are arranged essentially orthogonal to the wire in the wire guide element.

According to a further preferred embodiment of the present invention it is provided that the sensor device has an inductive displacement sensor. This enables the wire position to be determined without inaccuracies resulting from light reflections, for example. Inductive displacement sensors, like optical distance sensors, are standard components that have found widespread use in industry. However, it is also conceivable that the sensor device has a capacitive displacement sensor. It is also conceivable that the sensor device has an ultrasonic sensor or a sensor for measuring a phase shift, such as a laser interferometer, for example.

It is conceivable that the sensor device has at least one of the named sensors at one end of the wire guide element, a measuring section of the named sensor being aligned along the direction of the wire guide element. However, it is also conceivable that the sensor device has a plurality of said sensors along the direction of the wire guide element.

According to a further preferred embodiment of the present invention, it is provided that the opposite ends of the means for guiding the wire in the direction of the wire guide element each have an emergency switch. This advantageously enables the wire drawing device and / or the downstream processing machine to be switched off in an emergency or, in particular, also a second possibility of speed control as redundancy in the event of the failure of the sensor device.

It is preferably provided that the emergency switches are light barriers. Photoelectric barriers are ideally suited as emergency switches of the present invention. In order to fulfill the function as an emergency switch, a signal only needs to be output when the wire arrives at a certain position, here at the opposite ends of the shaft in the direction of the wire guide element. This can be done inexpensively and without wear with light barriers.

Furthermore, it is preferably provided that the emergency switches are mechanical switches. This enables the emergency switch to be switched safely without the risk of false tripping or incorrectly omitted tripping due to the occurrence of light reflections.

Another object of the present invention for solving the object formulated at the beginning is the method of claim 9 for operating a wire drawing device.

The method according to the invention enables the material properties of the wire not to be negatively influenced by the kickback force of a dancer arm and, in particular, not to be kinked. This is achieved by guiding the wire from the drawing disk in an arc essentially orthogonal to the direction of the wire guide element and typically within a plane which is parallel to the main extension plane of the drawing disk, through the wire guide element of the wire control device to the downstream processing machine and the position of the wire in the wire guide element is determined without contact.

The wire is continuously supplied from the drawing pulley. If the following processing machine now draws in wire discontinuously, the wire position in the wire guide element swings around a zero position. If the oscillation of the wire position is within a target range, the drawing disk supplies as much wire as is drawn in by the following processing machine on average over time. If the oscillation leaves the target range, the drawing pulley conveys more or less wire than the following processing machine on average over time draws in, the speed of the drawing pulley is regulated based on the distance between the vibration and the target range, so that the vibration returns to the target range and as much wire is supplied from the drawing pulley as the following processing machine draws in over time.

The direction of the wire guide element is preferably horizontal, particularly preferably the direction of the wire guide element is aligned horizontally and in the horizontal plane in a line with the drawing disk and the downstream processing machine.

It is conceivable that the wire drawing device is a wire drawing device according to one of Claims 1 to 8.

It is also conceivable that a frequency regulator is controlled to adjust the speed of the drawing disk, which in turn controls the drive of the drawing disk.

According to a preferred embodiment of the present invention it is provided that if the wire position deviates from a target range in a first direction along the direction of the wire guide element, the speed is increased and if the wire position deviates from the target range in a second direction along the direction of the wire guide element , the speed is reduced, the second direction being opposite to the first direction.

If the drawing disk conveys the wire on its side facing away from the downstream processing machine, the first direction is preferably directed essentially towards the drawing disk and the second direction is oriented essentially away from the drawing disk. If the drawing disk conveys the wire on its side facing the downstream processing machine, the first direction is preferably directed essentially away from the drawing disk and the second direction is oriented essentially toward the drawing disk. A control loop for regulating the speed of the wire is thus defined in an advantageous manner.

According to a further preferred embodiment of the present invention, it is provided that the wire position is determined with an optical distance sensor, preferably with a light barrier, particularly preferably with a distance-measuring light barrier.

This enables the wire position to be recorded quickly and reliably. It is conceivable that the wire position is determined by the optical distance sensor, the light barrier or the distance-measuring light barrier from one end of the wire guide element along the direction of the wire guide element. However, it is also conceivable that the wire position is determined by a light grid or a plurality of light barriers along the direction of the wire guide element.

According to a further preferred embodiment of the present invention it is provided that if it is determined by a first emergency switch that the wire position corresponds to a minimum wire position, the speed is increased and if it is determined by a second emergency switch that the wire position corresponds to a maximum wire position that Speed is reduced.

It is also conceivable that the drawing pulley and / or the downstream processing machine are stopped if a first emergency switch determines that the wire position corresponds to a minimum wire position or if a second emergency switch determines that the wire position corresponds to a maximum wire position.

This advantageously enables the wire drawing device to be switched off in an emergency or, in particular, also a second possibility of speed control as redundancy in the event of the failure of the sensor device.

According to a further preferred embodiment of the present invention it is provided that the strength of the acceleration or deceleration when regulating the speed based on the distance of the wire position from Target range is regulated. This enables a further improvement and refinement of the speed setting and thus protects the wire and the machines. It is also possible to avoid overshoots in the control.

Further details, features and advantages of the invention emerge from the drawings and from the following description of preferred embodiments with reference to the drawings. The drawings merely illustrate exemplary embodiments of the invention, which do not restrict the essential inventive concept.

Brief description of the drawings

Figure 1

According to an exemplary embodiment of the present invention, schematically shows a wire drawing device and a subsequent processing machine.

Figure 2

FIG. 12 schematically illustrates a wire control device in accordance with an exemplary embodiment of the present invention.

Embodiments of the invention

In the various figures, the same parts are always provided with the same reference numerals and are therefore usually only named or mentioned once.

In Figure 1 is a schematic view of a wire drawing device according to an exemplary embodiment of the present invention and a subsequent processing machine 12 shown. The drawing die 13 reduces the cross section of the wire 10. The wire 10 is conveyed at a speed in an arc to the downstream processing machine 12 via the drawing disk 11. The subsequent processing machine 12 removes the wire 10 at a further speed. Are the speed at which the pulley 11 pulls the wire 10 conveys and the further speed at which the downstream processing machine 12 picks up the wire is of different magnitude, so if there is a difference, the speed at which the drawing disk 11 conveys the wire 10 must be adapted. In order to measure the difference, the wire 10 is guided through the wire control device 1. In the wire control device 1, the wire position is measured without contact. If the speed at which the drawing disk 11 conveys the wire 10 is greater than the further speed at which the subsequent processing machine 12 picks up the wire, the length of the archwire is greater and the wire position shifts to the right in the drawing. If the speed at which the drawing disk 11 conveys the wire 10 is less than the further speed at which the subsequent processing machine 12 picks up the wire, the length of the archwire is shorter and the wire position shifts to the left in the drawing. These shifts in the wire position are detected by the wire control device 1 and the speed of the drawing disk 11 and thus the speed at which the drawing disk 11 conveys the wire 10 is adjusted so that the difference with the further speed at which the downstream processing machine 12 picks up the wire, Is zero.

In Figure 2 a wire control device 1 according to an exemplary embodiment of the present invention is shown schematically. The wire control device 1 has the housing 4 with the upper side part 4 ′, the lower side part, the right side part and the left side part, which is fastened to the holder 6. In the upper side part 4 'and in the lower side part gaps are attached which form the means 3 for leading the wire 10 (not shown here) of the wire guide element 2 through. When the wire control device 1 is in operation, the wire 10 is guided through the means 3 for passing the wire 10 through from the bottom to the top between the first emergency switch 5 and the second emergency switch 5 in the drawing. The wire position along the direction of the wire guide element 2 is determined by a distance-measuring light barrier (not shown). From the deviation of the wire position from a target position, the difference between the speed at which the drawing disk 11 (not shown here) conveys the wire 10 and the further speed at which the downstream processing machine 12 (not shown here) conveys the wire 10 takes up determined and the speed of the drawing disk 11 is adjusted so that the difference is zero. The setting of the speed of the drawing pulley 11 takes place via an electrical connection via the cable 7 from the wire control device 1 to the frequency controller of the drive of the drawing pulley 11. One of the two emergency switches 5 registers that the wire position corresponds to a minimum wire position or a maximum wire position and thus If the target value of the wire position deviates very much, the drawing disk 11 and the subsequent processing machine 12 are stopped or the speed of the drawing disk 11 is readjusted accordingly.

List of reference symbols

1

Wire control device

2

Wire guide element

3

Means for passing the wire through

4th

casing

4 '

Upper side part

5

Emergency switch

6th

bracket

7th

electric wire

10

wire

11

Drawing pulley

12th

Downstream processing machine

13th

Drawing die

Claims (13)

1. Wire drawing machine for reducing the cross section of a wire (10), wherein the wire drawing machine has a drawing block (11), wherein the wire drawing machine has a wire control device (1), wherein the wire control device (1) has a wire guide element (2) which extends in elongate fashion along one direction and which has means (3) through which the wire (10) is guided,
   wherein the wire drawing machine is configured in such a way that the wire (10) can be guided from the drawing block (11) in an arc, substantially orthogonal to the direction of the wire guide element (2), through the wire guide element (2) to a subsequent processing machine (12),
   characterized in that the wire control device (1) has a sensor device for the contactless determination of a wire position along the direction of the wire guide element (2).
2. Wire drawing machine according to the preceding claim, wherein the wire control device (1) has a housing (4), wherein the housing (4) has an upper side part (4') and a lower side part.
3. Wire drawing machine according to one of the preceding claims, wherein the means (3) through which the wire (10) is guided are a respective gap along the direction of the wire guide element (2) in the upper side part (4') and in the lower side part.
4. Wire drawing machine according to one of the preceding claims, wherein the sensor device has an optical distance sensor, preferably a light barrier, particularly preferably a distance-measuring light barrier.
5. Wire drawing machine according to one of the preceding claims, wherein the sensor device has an inductive displacement sensor.
6. Wire drawing machine according to one of the preceding claims, wherein the ends of the means (3) through which the wire (10) is guided, said ends being situated opposite one another in the direction of the wire guide element (2), have a respective emergency switch (5).
7. Wire drawing machine according to Claim 6, wherein the emergency switches (5) are light barriers.
8. Wire drawing machine according to Claim 6, wherein the emergency switches (5) are mechanical switches.
9. Method for operating a wire drawing machine, wherein a wire (10) is guided from a drawing block (11) of the wire drawing machine at a speed to a subsequent processing machine (12), wherein the wire (10) is guided through an elongate wire guide element (2) which extends along one direction,
   wherein the wire (10) is guided from the drawing block (11) in an arc, substantially orthogonal to the direction of the wire guide element (2), through the wire guide element (2) to the subsequent processing machine (12), wherein the speed is controlled on the basis of a wire position in the direction of the wire guide element (2) during the passage of the wire (10) through the wire guide element (2),
   characterized in that the wire position is ascertained in contactless fashion.
10. Method according to Claim 9, wherein, if the wire position deviates from a setpoint range in a first direction along the direction of the wire guide element (2), the speed is increased and, if the wire position deviates from the setpoint range in a second direction along the direction of the wire guide element (2), the speed is reduced, wherein the second direction is opposite to the first direction.
11. Method according to one of Claims 9 to 10, wherein the wire position is ascertained with an optical distance sensor, preferably with a light barrier, particularly preferably with a distance-measuring light barrier.
12. Method according to one of Claims 9 to 11, wherein, if a first emergency switch (5) ascertains that the wire position corresponds to a minimum wire position, the speed is increased and, if a second emergency switch (5) ascertains that the wire position corresponds to a maximum wire position, the speed is reduced.
13. Method according to one of Claims 9 to 12, wherein the intensity of the acceleration or deceleration during the control of the speed is controlled on the basis of the spacing of the wire position from the setpoint range.

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